Recombinant Human Interleukin-8 (CXCL8) (Active)
Description
Production and Quality Control
Commercial preparations meet stringent bioactivity standards:
Major expression systems include HEK293 cells (for post-translational modifications) and E. coli (for cost-effective bulk production) .
Immune Modulation
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Neutrophil activation: Induces Ca²⁺ flux (EC₅₀ = 2 nM) and respiratory burst via CXCR1
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Leukocyte recruitment: Binds glycosaminoglycans (GAGs) to create chemotactic gradients
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Cross-regulation: Competes with CXCL12 for bone marrow leukocyte retention/mobilization
Angiogenic Effects
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Endothelial proliferation: Stimulates VEGF production at 10 ng/mL
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Tumor progression: Enhances metastasis through MMP-9 upregulation (3-fold increase at 50 ng/mL)
Table 2: Experimental Use Cases
Clinical Relevance
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Atherosclerosis: Upregulated in plaques (3.8-fold vs. healthy tissue)
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COVID-19 complications: Serum levels correlate with ARDS severity (r=0.72)
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Therapeutic targeting: 23 clinical trials ongoing for anti-IL-8 therapies in oncology (as of 2023)
Stability and Handling
Product Specs
Generally, the shelf life of the liquid form is 6 months at -20°C/-80°C. The shelf life of the lyophilized form is 12 months at -20°C/-80°C.
Target Background
- VEGF and IL-8 play a prominent role in the pathogenesis of early forms of rosacea and the hemostasis system. PMID: 29578433
- High levels of LIFR in colorectal cancer (CRC) facilitate proliferation and migration of endothelial cells, leading to increased angiogenic activity. Furthermore, IL-8 was found to be involved in the LIFR-induced angiogenesis. IL-8 levels correlated with LIFR levels in CRC tissues, while depletion of IL-8 resulted in reduced angiogenic activity of LIFR in CRC cells. PMID: 29751081
- PKC-delta isoform plays a crucial role in Tat-TLR4 signaling pathway to activate NF-kappaB and CXCL8 production. PMID: 28539656
- CXCL8 was a target of miR-204, and miR-204 suppression could not increase cell viability, migration, invasion, and EMT procedure when CXCL8 was silenced. PMID: 29402343
- Interleukin 8 - 845 T/C and + 781 C/T polymorphisms were analyzed. For + 781C/T locus, in the dominant genetic model, a significant difference was observed between TT vs. CC + CT genotypes, indicating a protective role against periodontitis disease. A positive association was found between the distribution of IL8 - 845 T/C alleles and the risk of periodontitis disease. The C allele of IL-8 - 845 increased the risk of periodontitis disease. PMID: 30078118
- These results suggest a direct involvement of IL-8-CXCR1/2 axes in GBM progression by promoting both cell proliferation and invasion, and indirectly by promoting neovascularization in the form of vascular mimicry. PMID: 30086759
- These results indicate that AKIP1 is crucial in cervical cancer angiogenesis and growth by elevating the levels of NF-kappaB-dependent chemokines CXCL1, CXCL2, and CXCL8. PMID: 29520695
- The extramembranous domain of HofQ (emHofQ) was shown to interact with various cytokines, among which IL-8 exhibited the strongest interaction. PMID: 30088437
- The protein expression levels of IL-8 were significantly decreased in SZ patients, but no significant difference in the mRNA levels of IL-8 was observed between SZ patients and NC subjects. PMID: 28476335
- The immune system process is indispensable in the progression of disease in the colon, and it identifies that IL-8 and MMP-9 play potential critical roles for the progression. PMID: 30074183
- IL-8 production was significantly enhanced following treatment with both IL-17A and CSE, while treatment with either IL-17A or CSE alone caused only a slight increase in IL-8 production. PMID: 29463070
- This work identified IL-8 as a positive regulator of homotypic CIC formation via enhancing intercellular adhesion. PMID: 30021676
- V2O5 induction of CXCL8 and CXCL11 chemokines may lead to the appearance and perpetuation of an inflammatory reaction in the dermal tissue. Further studies are needed to evaluate dermal integrity and manifestations in subjects occupationally exposed, or living in polluted areas. PMID: 29901202
- Study findings suggest that PAR2 could play an essential role in gastroesophageal reflux disease (GERD) pathogenesis - even repeated short-term exposure to weakly acidic conditions leads to the upregulation of PAR2 and subsequent activation of the intense IL-8 release in the esophageal mucosa, initiating a mucosal immune response in GERD. PMID: 29672302
- Considering that IL-8, MIP-1beta, and MCP-1 are chemokines that play important roles in the recruitment of immunocompetent cells for immune defense and tumor cell clearance, the observed lower levels of these markers with increasing PM2.5 exposure may provide insight into the mechanism by which DEE promotes lung cancer. PMID: 29023999
- These results suggest that stemness induction in SKOV3 cells by macrophages co-cultured with SKOV3-derived OCSLCs involved IL-8/STAT3 signaling. PMID: 29656182
- IL-8-251T>A (rs4073) Polymorphism is associated with gastric Cancer. PMID: 30275190
- The expression level of CXCL8 had a positive relationship with recurrence probability in Acute myeloid leukemia. PMID: 29596823
- These data were consistent with the reduced cell migration and colony formation. Results from the present study suggest that reparixin and SCH527123 may be promising therapeutic agents for the treatment of pancreatic cancer by inhibiting the IL8/CXCR1/2 signaling cascade. PMID: 29749433
- A urinary IL-8 level of less than 61.25 pg/ml is more sensitive for predicting complete remission in idiopathic membranous nephropathy patients. PMID: 29415357
- Berberine inhibited the expression of MCP-1 and IL-8 induced by LPS. PMID: 28852897
- Regarding the IL-8 promoter T - 251A, the TA and AA genotypes were associated with significantly decreased risks of nasopharyngeal carcinoma (NPC) in a Taiwanese population compared with the wild-type TT genotype. The mRNA and protein expression levels for NPC tissues revealed no significant associations among the 20 NPC samples with different genotypes. PMID: 30200105
- IL-8 +781 T/C polymorphism is associated with severe Clostridium difficile infection. PMID: 29203364
- ShRNA mediated down-regulation of CXCL8 resulted in inhibition of cell proliferation, viability and invasion in vitro and a near complete growth reduction of tumor in vivo. PMID: 29679563
- CSF IL-8 concentrations were significantly elevated in CNS tumor patients compared to non-tumoral individuals. AUC for CSF IL-8 was higher than for its index (CSF IL-8/serum IL-8). PMID: 29086194
- High IL8 expression is associated with melanoma. PMID: 29286146
- Lipo-CPFX, but not CPFX, retained the anti-IL-8 releasing activity. PMID: 29337216
- The results indicate a significant contribution of IL8 on the survival of hormonal dependent early-stage breast cancer patients and association with established parameters such as estrogen receptors/progesterone receptor and HER2. PMID: 28569250
- The frequency of non-classical monocytes expressing CXCL8 was increased in systemic sclerosis patients, and monocytes expressing CXCL8. PMID: 29127442
- Intermediate Molecular Mass Hyaluronan and CD44 interactions enhanced normal PMN phagocytosis and IL-8 production. PMID: 28730511
- Serum levels in active vitiligo were significantly elevated compared to those in stable vitiligo patients. PMID: 29115683
- High IL8 expression is associated with pancreatic adenocarcinoma. PMID: 29205349
- Compared to controls, the interleukin (IL)-8 A/A genotype was more common in acute pancreatitis (AP). PMID: 29215544
- The presence of neither the first transmembrane helix of the receptor nor the lipid bilayer significantly affected the interactions of IL-8 with Binding Site-I of CXCR1. PMID: 29143165
- CXCL8 is highly expressed in cervical cancer tissues and cell lines, and correlated with malignant status and prognosis in cervical cancer patients. PMID: 28883082
- In conclusion, to our knowledge, this is the first study in the association of rs4073 and rs2227306 polymorphisms with childhood asthma risk in the Tunisian population. PMID: 28993876
- Results show that IL8 expression level is regulated by APE1 which activates NF-KB. PMID: 27388124
- Aberrant miR-520c-3p expression may lead to reduced IL-8 expression and promote the mesenchymal phenotype in breast cancer cells, thereby increasing invasive growth. PMID: 29048659
- Increased levels of IL-8 are associated with factors of worse prognosis in ovarian cancer. PMID: 28872976
- Significantly elevated blood levels of IL-8 in myelodysplastic syndrome patients. PMID: 28856536
- The elevated concentrations of CXCL13, CXCL8, and CXCL10 or their increasing CSF/serum ratios may be potential biomarkers of neurosyphilis. PMID: 27650493
- Results implicated the important role of PRL-3 in glycolysis metabolism through improving IL-8 secretion in colorectal cancer cells, and PRL-3 mediated glycolysis contributed to the promotion of cancer metastasis. PMID: 28791350
- Changes in serum IL-8 levels could be used to monitor and predict clinical benefit from immune checkpoint blockade in melanoma and NSCLC patients. PMID: 28595336
- Lung cancer patients showed significantly lower levels of serum VEGF (1.9 fold) and IL-8 (~9 fold) than COPD patients. VEGF level was significantly higher (2.6 fold) in metastatic than non-metastatic cancer patients. An increase in MMP-9 (~1.6 fold) levels was observed in lung cancer patients. PMID: 27811960
- CXCL1/8 secreted by adipose-derived mesenchymal stem cells could promote breast cancer angiogenesis. PMID: 28514506
- Our meta-analysis suggests that the IL-8 rs4073, A2767T, T11722T2, rs2234671, rs2230054, rs1126579, rs2227306, rs2227307, rs2227532, and T-738A polymorphisms are not associated with periodontitis, while the IL-8 C1633T and rs1126580 polymorphisms may elevate the susceptibility of periodontitis based on the currently available evidence. PMID: 28446725
- An analogue of human CXCL8, CXCL8(3-72)K11R/G31P (hG31P) has been developed. PMID: 28754019
- Inflammation triggered property of Microcystin-LR via IL-8/CXCR2 signaling. PMID: 29197248
- A high IL-8 content in urine sampled on day 1 after renal transplantation was positively correlated with the activity of metalloproteinase-9 in urine. This demonstrates that both of these chemokines cooperate in ischemia-reperfusion injuries in transplanted kidneys. PMID: 28494217
- We discovered that IL-8 secreted from decidual stromal cells is a key cytokine enhancing the invasiveness of trophoblasts. PMID: 28328096
Q&A
What is the structural composition of recombinant human IL-8/CXCL8?
Recombinant human IL-8/CXCL8 is an 8-9 kDa chemokine belonging to the CXC family. The commercially available protein is typically E. coli-derived and encompasses amino acids Ser28-Ser99 of the human sequence. It contains an ELR motif near its N-terminus that is crucial for its angiogenic properties . The protein can exist in multiple forms including monomers and dimers, with the ability to form homodimers or heterodimers with CXCL4/PF4 . Under SDS-PAGE reducing conditions, recombinant human IL-8/CXCL8 appears as a single band at approximately 8 kDa .
How does IL-8/CXCL8 function in inflammatory responses?
IL-8/CXCL8 functions as a proinflammatory mediator primarily through interaction with two receptors: CXCR1 and CXCR2. Through these receptors, IL-8 promotes neutrophil adhesion to vascular endothelium and mediates migration to inflammation sites . Specifically, IL-8 triggers antimicrobial activation of neutrophils through CXCR1 . Additionally, IL-8 induces VEGF expression, promotes vascular endothelial cell proliferation, and stimulates angiogenesis . The bioactivity of IL-8/CXCL8 is regulated by N-terminal truncations, citrullination at Arg5, and interaction with the decoy receptor DARC .
What are the recommended reconstitution procedures for lyophilized recombinant human IL-8/CXCL8?
Recombinant human IL-8/CXCL8 is typically supplied in lyophilized form and requires proper reconstitution to maintain bioactivity. For carrier-containing formulations (with BSA), reconstitute at 100 μg/mL in sterile PBS containing at least 0.1% human or bovine serum albumin . For carrier-free formulations, reconstitute at 100 μg/mL in sterile PBS without additional protein . Following reconstitution, the solution should be aliquoted to avoid repeated freeze-thaw cycles that can compromise protein activity. Storage should be in a manual defrost freezer to maintain stability .
What is the difference between carrier-containing and carrier-free recombinant IL-8 formulations?
Carrier-containing formulations of recombinant IL-8 include Bovine Serum Albumin (BSA) as a carrier protein, which enhances protein stability, increases shelf-life, and allows for storage at more dilute concentrations . These formulations are recommended for cell or tissue culture applications and as ELISA standards. Carrier-free formulations do not contain BSA and are preferred for applications where the presence of BSA could potentially interfere with experimental outcomes . The absence of carrier protein in these formulations necessitates more careful handling to maintain protein stability.
How should recombinant IL-8 be used in neutrophil migration assays?
For neutrophil migration assays, recombinant human IL-8 is typically used at concentrations ranging from 0.5-100 ng/mL, with significant effects observed at 100 ng/mL where neutrophil migration increases by approximately 25% . To establish a chemotactic gradient, add recombinant IL-8 to the lower chamber of a transwell system while placing neutrophils in the upper chamber. For more complex in vitro models, a co-culture system can be established using appropriate endothelial and epithelial cell lines on collagen-coated inserts to study neutrophil migration across multiple tissue layers in the correct sequence . A dose-response curve should be generated to determine optimal concentration for specific experimental conditions, as IL-8 exhibits dose-dependent effects on neutrophil chemotaxis.
What are the functional differences between monomeric and dimeric forms of IL-8 in receptor activation?
Monomeric and dimeric forms of IL-8/CXCL8 exhibit distinct activities in receptor activation and downstream signaling. The monomeric form demonstrates higher activity than the dimeric form for several cellular responses including intracellular Ca²⁺ mobilization, phosphoinositide hydrolysis, chemotaxis, and exocytosis . The regulation mechanisms also differ between receptors: for CXCR1, monomeric IL-8 induces more rapid receptor phosphorylation, desensitization, β-arrestin translocation, and internalization compared to dimeric IL-8 . In contrast, CXCR2 responds similarly to both monomeric and dimeric IL-8 for these regulatory processes . ERK phosphorylation is more sustained in response to both forms of IL-8 for CXCR2 relative to CXCR1 . These differential activities have significant implications for experimental design when studying specific receptor-mediated pathways.
How can recombinant IL-8 be used to investigate cell survival mechanisms?
Recombinant IL-8 has been demonstrated to play a critical role in cell survival mechanisms, particularly in urothelial cells. To investigate these survival pathways, researchers can employ RNA interference techniques to suppress endogenous IL-8 production. When normal urothelial cells are treated with IL-8 siRNA, they undergo cell death, rounding up and detaching from culture plates . Supplementation with recombinant IL-8 (500 ng/mL) rescues these cells from death, confirming IL-8's essential role in cell survival . The rescue effect can be blocked by anti-CXCR1 antibodies but not by anti-CXCR2 antibodies, indicating that IL-8's survival-promoting effects are primarily mediated through CXCR1 . This experimental approach allows for detailed investigation of IL-8-dependent survival pathways and receptor-specific signaling mechanisms.
What strategies can be employed to study differential receptor activation by IL-8?
To study differential activation of CXCR1 and CXCR2 by IL-8, researchers can utilize trapped monomers (e.g., L25NMe) and nondissociating dimers (e.g., R26C) to compare receptor-specific responses . Cell lines stably expressing either CXCR1 or CXCR2 (such as RBL-2H3 cells) provide isolated receptor systems, while human neutrophils offer a natural model expressing both receptors . Key readouts to assess include: calcium mobilization, phosphoinositide hydrolysis, chemotaxis, exocytosis, receptor phosphorylation, and β-arrestin translocation . For signaling pathway analysis, measure ERK phosphorylation kinetics, which shows receptor-specific patterns (more sustained for CXCR2 than CXCR1) . Additionally, receptor internalization assays using fluorescently labeled antibodies or tagged receptors can reveal differences in receptor regulation.
How does IL-8 expression vary between normal and pathological tissues?
Studies comparing IL-8 expression between normal and pathological tissues reveal significant differences that may impact experimental design. In normal bladder/ureter tissues, IL-8 expression is predominantly positive (5 out of 6 samples), while in interstitial cystitis (IC) patients, IL-8 expression is frequently negative (9 out of 13 samples) . This differential expression pattern is statistically significant (p < 0.05) and has implications for research on inflammatory conditions. The table below summarizes these findings:
| IL-8 Status | Positive | Negative |
|---|---|---|
| Normal | 5 | 1 |
| IC | 4 | 9 |
When designing experiments involving IL-8 in tissue samples, researchers should consider these intrinsic expression patterns and potentially stratify samples accordingly. Control tissues may have higher basal IL-8 expression than certain pathological tissues, which could affect interpretation of exogenous IL-8 effects .
What concentrations of recombinant IL-8 are biologically relevant for in vitro studies?
The biologically relevant concentration of recombinant IL-8 varies by application and cell type. For neutrophil chemotaxis assays, concentrations between 0.5-100 ng/mL show dose-dependent effects, with 100 ng/mL increasing migration by approximately 25% . The ED50 for IL-8's chemoattractant effect on BaF3 cells transfected with human CXCR2 is 0.5-2.5 ng/mL . For cell survival studies with urothelial cells, 500 ng/mL of recombinant IL-8 effectively rescues cells from siRNA-induced death . When designing experiments, dose-response curves should be generated for the specific cell type and measured outcome. Additionally, researchers should consider that physiological IL-8 concentrations can fluctuate dramatically during inflammatory conditions, so using a range of concentrations may better mimic in vivo scenarios.
